Just got T2 and so far loving the way it connected and sends data to my A3. Ran in to a problem today and was hoping someone could help

I made a graphic in Corel Draw to go on a 4" x 4" slate tile with a wine glass on it. The wine glass is not the full size but instead smaller. I exported it as a BMP and then opened it up in T2 (imported just fine as you can see by first pic and I went to output size and it had it as 120mm so I resized it to 101.6 x 101.6 (4") and when I did part of the stem disappeared (second pic below) . Then I found that the smaller I made the image the more of the graphic disappeared. Any ideas?

Ordered my first laser (Eleksmaker A3 2.5 Watt) and while waiting for it to arrive I am getting everything ready and doing as much research as possible as this is my first attempt with Lasers.

My plan is to do some engraving only (no cutting) so here are some questions if anyone can help...

I currently use Corel Draw and what i prefer for creating all of my graphics (right now I do sublimation and vinyl work) so i work with vectors a bit in Corel. What is the best choice of software that will allow me to import my images / text from Corel Draw and send to laser?

Does anyone have a info sheet or anything on recommended speeds and power for different types of substrates? Like I said right now my plan is to engrave only and planning on some wood projects, slate etc.

I plan on using air assist as I have heard recommendations to have a cleaner engraved image and to minimize smoke on the lens. I already purchased a small suitable compressor and those blue flexible modular coolant hoses. My question is where and how is the best method for mounting the hoses?

Do most of you find it easier to send something to test first on say something like cardboard or something else to test priot to engraving on final substrate?

And finally.... (eben tough I am sure I will have more questions LOL) What and how is the best method for positioning the substrate in the laser frame to get the engraving to be centered? Do you guys mark out a grid or something showing a center?